Fuse block for thermal cut-outs



Patented Oct. y22, 1929v UNITED STATES JACOB M. FRIED, F VICKSBURG, MISSISSIPPI FUSE BLOCK FOR THERMAL CUT-CUTS Application filed November 1, 1928. Serial No. 316,558.

This invention relates to thermal cut-outs of the plug and socket type and consists in the provision of an improved construction and arrangement of socket contacts whereby short circuiting of said contacts by packing the socket with tin foil or restoring to to other expedients is rendered exceedingly diiicult.

More particularly the invention consists in an improved construction and arrangement of socket contacts particularly adapted for application to fuse blocks of the type disclosed in my prior Patent 1,668,450 issued May 1st, 1928.

Other characteristic features and advantages of the invention will be more readily understood from the following detailed description and accompanying drawings in which:

constructed in accordance with my invention;

Figure 2 is a bottom plan view;

Figure 3 is a vertical sectional view taken along the line 3 3 of Figure 1;

Figure 4 is a vertical sectional view taken along the line 1f-4 of Figure 1, and,

Figure 5 is a view in side elevation of a fuse plu employed in connection with the fuse bloei shown in the preceding figures.

As illustrated in the accompanying drawings, the fuse block 5 is provided with a socket 6 having a bottom wall 7 in the center of which is formed a relatively deeprecess 8.

Resting on the bottom wall 7 and secured thereto by bolts 9 is a threaded metallic sleeve 10 having its upper edge terminating below the mouth of the socket 6. One of the fuse block contacts is positioned at the bottom of the recess 8 and consists of a conductor 11 passing downwardly through a suitable opening 12 formed in the lower portion of the block 5. The upper end of the conductor 11 is upset to form a contact head 13 while the lower portion of the conductor is bent to extend horizontally within a suitable groove 14 and is adapted to be secured to any suitable form of terminal, not shown, subsequent to which the groove 14 is filled with a suitable insulating compound 15. The

Figure 1 is a top plan view of a fuse blockv other contact of the fuse block is in the form of a conductor 16 which is inserted in a vertical passage 17 formed in the block 5 at one side of the socket 6, the lower end of the conductor being bent to extend horizontally within a second groove 18 and connected to the remaining terminal, not shown, of the fuse block, subsequent to which the groove 18 is also filled with an insulating compound 15. rlLhe upper end of this conductor is bent as indicated at 19 to provide a spring contact projecting into the socket 6 above and in spaced relation to the upper edge of the metal sleeve 10, there being a. suitable recess 20 formed in the upper edge of the socket 6 to permit the spring contact 19 to be forced back when the fuse plug is inserted in the socket as hereinafter described.

The yfuse plug shown in Figure 5 is constructed as disclosed in my prior patent previously referred to, and consists of a body of insulating material having its upper portion surrounded by a threaded metallic sleeve 21 adapted to be screwed into the sleeve 10 of the socket 6, the lower body portion of the plug being in the form of an extension 22 adapted to be snugly received in the recess 8 and having a suitable contact tip 23 engageable with the contact 13, said contact tip 23 being connected to the sleeve 21 of the plug by an interior fuse wire, not shown. Then the fuse plug is threaded into the socket thc sleeve 21 is engaged by the spring contact 19 to complete the circuit connections between the plug and the fuse block.

Ordinarily the threaded metal sleeve 10 is employed as one of the block contacts but it has been found that when this is the ease it is a comparatively easy matter to short circuit the fuse block contacts by packing the socket 6 and the recess 8 with tinfoil. This expedient for short circuiting the fuse plug is made more difiieult with the present invention by reason of the fact that the spring contact 19 presents only a relatively small area of contact surface with which it is diicult to keep the tinfoil in such engagement as to effect the desired electrical connection between the fuse block contacts.

While in the present instance the contact Vsleeve 10 is shown of less height than the socket 6 it Will be understood that theY said sleeve may extend the full height of the socket provided that a lateral opening is made in the sleeve to receive theinwardly projecting spring contact 19.

Having thus described what I now conceive to be the preferred embodiment of the invention it will be understood that various changes in the construction and arrangement of parts may be resorted to Within the scope of the appended claims.

What I claim is:

l. A fuse block provided With a plug .re-v I. ceiving socket having a Contact positioned in the ylower portionthereoin va threaded yinetallic sleeve arranged in the upper portion of the socket anda second yieldingly mounted Contact projecting laterally into the upper portion of .said socket in spaced relation lto said sleeve.

2. A fuse block havin ga socket, a threaded metal-sleeve secured in said socket and adapted to engage the threaded Contact sleeve of a fuse plug designed for use in' connection With said socket, a contact on the bottom Wall of the socket adapted to engage one of the plugv contacts and a second yieldingly mounted contact projectingiinwardly from an upper Wallportion of the socket, both of said socket contacts being insulated from one another and. from the/sleeve secured in the socket. Y v

3. A fuse block provided with a plug receiving socket having a contact positioned in the lower portion thereo, a threaded section arranged in the upper portion of the socket and a second yieldingly mounted con,

tact projecting laterally into the upper portion of said socket in'spaced relation to said threaded section. In testimony Whereoi` I hereunto affix my. signature.

JACOB M. Flainn l 

